Art of folding leather



. March 6, 1928 C. K. M DONALD ART OF FOLDING LEATHER Filed Dec. 1923 zavagygmagylavzuim 33 1;;

Patented Mar. 6, 1928.

UNITED STATES PATENT OFF1E.,

CLIFFORD K. MACDONALD, OF BROCIKTON, MASSACHUSETTS, ASSIGNOR TO UNITED SHOE MACHINERY CORPORATION, OF PATERSON, NEW JERSEY, A CORPORATION OF NEW JERSEY.

ART OF FOLDING LEATHER.

' Application filed December 31, 1923. Serial No. 683,682.

' This invention relates to folding the margins of pieces of sheet material such as leather parts of uppers of boots and shoes in order to produce nished edges thereon.

In the manufacture of boots and shoes it has been customary to skive the margin of a shoe part, such for example as a tip, to coat the skived margin with an adhesive substance and then to fold the margin. In

ractice the width of the fold is in the neighiiorhood of three-sixteenth's of an inch, the Width of the scarf being substantially twice that so that the folded edge will have approximately the same thickness as the original thickness of the leather. A fold of this Width consumes a considerable amount of leather, the aggregate being very large. Be-',

cause of the high cost of leather, it is very desirable that the fold be as narrow as possible, but hitherto no method of cementing and folding has been devised which will produce a satisfactory fold appreciably narrower than the standard fold referred to above.

In one aspect the invention consists in a method consisting in coating the margin on one side of a piece of material with an adhesive substance which contracts upon application to it of heat, applying heat whereby the extreme margin curls toward the coated side, and pressing the curled margin over upon the material. Preferably, a scarf is first produced on the. margin and the adhesive substance is applied to the scarf the completed fold will be substantially the same as the original thickness of the material. By using an adhesive substance which has the contractile property referred to above as Well as the capability of producing a firm bond, a satisfactory fold can be made which is only from onehalf to one-third or even a smaller fraction of the Width of the standard fold now in use. The initiation of the fold by causing the extreme margin of the material to be bent upwardly may be facilitated if desired by forcing the edge of the material against an obstruction, such as a properly shaped gage; and the width of the fold may be controlled for example by limiting the extent to which the edge of the curled portion may be pushed. up the work-engaging face of the s e' .after laying the bent In the folding of boots and shoes, it has been common to use a cement which is normally tacky, a common procedure being to coat one side of the margin with rubber cement, wait until the cement becomes properly tacky and then fold the margin and press the fold. Cement of this general type remains properly tacky only for an interval and the folding must therefore be done during this interval. In another aspect, the invention relates to a method of folding which comprises coating one side of the margin of the work with a cement which is normally non-tacky, rendering the cement tacky by applying heat to the margin of the material, imparting a bend to the margin while it is heated and theremargin over upon the body portion of the work. IVith this method it is possible to permit the work, the margin of which has been coated with a normally non-tacky cement, to stand for an indefinite interval before being operated upon, and still ensure that the cement shall be properly softened before the bent margin is pressed down upon the. body portion of the work.

In another aspect the invention consists 1n a machine by which certain steps of the method, such as the initiating and pressing of the fold, may be facilitated and accu rately controlled. According to one feature of the invention, there is provided a support over which the material is fed, means for heating the margin of the material and for initiating the fold, and means for thereafter pressing the fold. In the illustrative machine the heat is applied through the edge gage and the support, both of which are formed at the outer end of a rotating shaft; and the edge of the material is forced against the gage by a slender shaft which of the margins of parts shaft which overlies both the gage and the I gage.

. ings,

adjacent portion of the support for the material and extends close to the top of the This slender shaft serves not only to limit the extent to which the edge of the curled position of the material may be pushed upwardly but, by its rotation, lays the" upwardly curled or bent portion over u on the material.

Referring now to the accompanying draw- Figure 1 is a perspective of a folding machine. 1

Figure 2 is a plan of the members which engage the work.

Figures 3, 4and 5 are views partly in section and partly in elevation showing differdent stages in the operation upon the work, an

F1 re 6 is a view similar to Figure 5 but showing a modified form of gage.

F igures' 3 to 6 in clusive are upon a greatly enlarged scale. k

The work 100'is first skived on an abrupt angle so as to produce anarrow scarf. This scarf is coated-with an adhesive substance such for example as a solution of guttapercha in carbon tetrachloride and. allowed to dry. The dry coating is not-tacky but will become so upon being subjected to a moderate heat and will also contract. The leather piece is presented in the manner shown in Figure 3 upon a work support 7, herein shown as the cylindrical reduced end of a rotary shaft 9, which is heated by fric-\ resently appear, with the thin edge of the eather in contact with an edge gage in the form of a shoulder 11 formed at the junction of the reduced portion 7 with the main portion of the shaft 9,. A slender rotary shaft 13, which is rotated in the direction indicated by the arrow, forcibly tion as will crowds'the edge of the scarf against the margin of. the leather to be shoulder or obstruction 11 by moving the leather to the right. The effect of this crowding and of the application of heat through the shaft 9 is to cause the extreme bent, upwardly in the manner shown in Fig. 4. In order to limit the extent to which the thin edge of the leather may be pushed upwardly, as well as for other purposes presently to be described, a second slender shaft 15 extends over the shoulder 11 in close proximity thereto and over the work support '7. This shaft is rotated in a direction opposite to that of the shaft 13 and acts not only to limit the extent of upward movement ofvthe thin edge of the leather due to the pushing 'of the leather to the right by the shaft 13,

but also tolay the upwardly bent margin.

over upon the leather and to press or rub it into place as indicated in Fig. 5. The shafts 13 and 15' are substantially parallel; and inorder to cause the work to be fed by them past the gage or shoulder 11, the workthe threads,

engaging ends ofone or'both of the shafts are threaded. If both are threaded, then .viewed in Figure 2.

Referring now more particularly to Figure 1, the shaft 9 is rotatable in alined horizontal bearings earned by two upwardly extending 'portions of the frame 17 and has fast to its inner end a generally cylindrical member 19 which is frictionally driven by contact with a friction disk 21 fast to the lower face of a pulley 23 which is rotatable about an inclined spindle 25 carried by the frame of the machine. Integral with the pulley is a pulley 27 which is rotatedthrough a belt 29 from any suitable source ofv power. Located above the pulley 27 and loose on the spindle 25 is a pulley 31, the three pulleys being prevented from upward movement by a set collar 33. Fastened respectively to the outer 'ends of the shafts 13 and 15 are small pulleys 35 and 37; and

a capable of regulation. The shaft 13 is rotatably mounted in a sleeve 41 carried at the outer end of an arm 43 which is pivoted to 'the frame of the machine at '45. A tension spring 47 connected at its upper end to the arm and at its lower end to the frame tends at all times to pull the arm downwardly, the extent of this downward movement being limited by an eccentric 48 having a head or finger piece 49 by which it may be turned; The eccentric supports the arm 43 against the downward pullof the springand thus determines the position of the shaft 13 above the work support. One function of this shaft, as has been explained, is to move the work to the right as viewed in Figs. 3 to 5, and thereby to crowd the edge of the work forcibly against the shoulder 11. The force exerted for this purpose by the shaft 13 depends upon how firmly it is permitted to press the work against the support 7 under the action of the spring47; and the degree of this firmness may be varied by turning the eccentric 48 into different positions.

The shaft 15 is rotatably mounted in a sleeve 52 similar to the sleeve 41 and similarly carried by an arm 53 which issubstantially like the arm 43 and is pivoted to the frame. of the machine at a point (not shown), but lying'in the axis of the pivot 45. A tension spring 55 of less strength'than'that. of the spring 47 'Urgesihis arm downwardly at all times, the extent of the ,downward\ movement being adjustably controlled by a set screw 57 which is threaded through a lug 59 on the arm 53 and contacts at its lower end with a lug 61 on the frame of' the machine.-

hesive coating on the scarf of the material tacky and contractile is applied to the uncoated side of the material. In the illustrative machine the shaft 9 is'heated by a friction plug 03 of wood which extends through a hole in the bottom of a hollow cylindrical lug 65 which is" rigid with the frame of the machine. is acted upon by a spring 67 the tension of which may be varied by turning a screw (39, said screw being threaded into the upper end of the cylindrical. lug and bearing upon the top of the spring. Although a frictional eating means has been shown, any other suitable heating means may be employed.

In Fig. 6 there is shown a modified form of work support and gage 107 which is stationary instead of rotatable. This work support and gage is designed more particularly for use in folding the inside edge of a vamp 200, the stem 109 extending upwardly so as to permit the legs of the vamp to be swung beneath it when, as shown, the edge of the throat of the vamp is being operated upon. The stem 109 of this work support and gage-may be fastened in any suitable manner as by a cap screw 164 to the frame of the machine; and heat may be applied to it or to the work support in. any suitable manner conveniently for example by an electric heating unit 163.

Although the invention has been setforth in connection :with a particular machine and a particular kind of work, it should be understood that the invention is not limited in the scope of its application to the particular machine or work .which has been shown and described.

Having thus described my invention, what I claim as new and desire to secure by Letters, Patent of the United States is:

1. The method of folding a piece of sheet material which comprises skiving the margin, coating the margin with an adhesive substance which contracts upon application to it of heat, applying heat to the margin whereby the margin is caused to curl toward the coated side. and pressing the curled margin upon the material.

2. The method of folding a pi'cce of sheet material which comprises skiving the margin, coating the margin with an adhesive substance which contracts upon application .to it of heat, applying heat to the uncoated side of the margin whereby the margin is caused to curl toward the coated side, andpressing the curled margin upon the ma terial.

a The method offolding a, piece of sheet The head'of the plug.

material which comprises skiving the margin, coatingv the margin with an adhesive substance which contracts upon application to it of heat, forcing the edge against a I heated obstruction whereby the contraction ffreferably the heat which renders the 'ad- 4. A machine for folding the margins of parts of the uppers of boots and shoes .havmg, in combination, a support for the work,

an abutment projecting therefrom, means for feeding the work past the abutment, for forcing the edge of the work against the abutment in a direction at an angle to the line of feed so as to cause the margin of the work to be bent at an angle to the body of. the work, and for pressing the entire extent of the bent margin upon the body of the work, and means for applying heat to the margin of the work prior to the pressing of the margin. Y

5. A machine for folding the margins of parts of the uppers of boots and shoes having, in combination, a'support for the work, an abutment projecting therefrom, mcans for feeding the work past the abutment, for

-ment, for forcing the edge of the work against the abutment to cause the margin of the work to be bent at an angle to the body of the work and for pressing the entire ex tent of the bent margin upon the body of the work, and means for applying heat to' the margin prior to the-pressing thereof.

7. .A folding machine having a support for the work, a member projecting therefrom to form a shoulder, and means for feeding the work past the shoulder, for forcing the edge of the work against the shoulder to cause the margin to be bent at an angle to the body of the work and for pressing the bent margin upon the body of the work. said 'means'comprising a rotary member extendmg in the direction of feed movement of the Work and having threads thereon arranged to feed the work.

8. A folding machine having a supportfor the work, a member projecting therefrom to form a shoulder, means for feeding the work past the shoulder, for forcing the edge of the work against the shoulder to cause the margin to be bent atan angle to the body I l the margin of the work to gin upon the bodyo of the work and for ressing the bent marthe work, said means comprising a rotary member having threads thereon; and means for rotating said member about an axis which extends substantially in the direction of feed movement of I the Work.

, to engage the edge of the work as the work passes through the machine, means for heat-- ing the work through one of said, members, and a rotar member threaded to cause 'it when rotated to feed the work and arranged to engage the work close to the gage.

11. A folding machine having, in combination, a support, a gage member adapted to engage the edge of the work as the work passes through the machine, a .folding' and work feeding member in the form of a shaft extending in the direction of feed movement arranged to engage the work close to the gage and means for rotating the shaft, said I shaft having work-feedingfthreads on its work-engagin portion.

v 12. A machine for folding the margins of parts of the uppers of boots and shoes having, in combination, a work support, a gage extending above the support, means for preventing the edge of the work from rising above the top of the gage, means for crowd mg the edge of the work against the gage .with a force suflicient to cause the margin of the work to be, bent upwardly, means for bending the margin over upon thebody portion of the work and for pressing the entire extent of the bent margin, and means for heating the gage. I

13. A folding machine having, in combination, a work support, a gageextending above the support, means for preventing the edge of the work rising above the top of the gage, and a rotary member adapted to engage tlieunfolded portion of the work for crowding the edge of the work against the gage with a. force suflicient to cause the margm of the work to be bent upwardly, said member being threaded to cause the work to be fed.

. spaced from the shoulder and to bend the- 14, A folding machine having, in combination, a work support, a member extending above the support to form a shoulder which serves as a guide' for the edge of the work, a rotary member extending over the support and adapted to engage the work at a locality edge of the work against the shoulder, and

a second rotary member extending over the shoulder and adapted to engage the work at a locality close "to the shoulder, and to lay the upwardly bent margin over upon the body of the work.

15. A'folding machine having, in combi- I nation, a work support, a member extending above the support to form a shoulder which serves as a guide for the edge of the work,

and adapted to engage the work at a locality spaced from the shoulder and to bend the margin of the work upwardly by forcing the edge of the work against the shoulder, a sedover the work support, one shaft being adjacent to and the other spaced from the gage, means for rotating the spaced shaft in a direction 'to force the work against the gage so 'as to bend the edge of the Work upwardly and means for rotating the other shaft in the opposite direction, one of said shafts hava rotary member extending over the, support ing its work-engaging portion threaded to 0 feed the work past the gage.

17. A folding machine having, in combination, a work support, an edge gage a pair of substantially parallel shafts extending over the work support, one shaft being adjacent to and the other spaced fromflthe gage, means for rotating the spaced shaft in a direction to force the work against'the gage so as to bend the edge of the work upwardly, means for rotating the other shaft in the opposite direction, one of said shafts having its work-engaging portion threaded to feed the work past the gage, and means for ap plying heat to the margin of the work.

18. A folding machine having, in combination, a support for the work, an edge gage, two rotary shafts having their engaging portions threaded in opposite directions, means for rotating said shafts in opposite directions, and yielding means operating to move the shafts toward the support and hold them in contact with the work.

19. A folding machine having, in combination, a support for the work, an edge gage two rotary shafts having their engaging portions threaded in opposite directions, means for rotating said shafts in opposite directions, yielding means operatingto move the shafts toward the support and .hold them independently of each other the degree of 20. folding machine having, in combination, a support for the work, an edge gage,

and two rotary shafts arranged in substantially parallel relation and extending over the support in position to engage the work. I

21. A folding machine having, in combination, a support for the work, an edgegage, means for applying heat to the work, and two rotarv' shafts arranged in substantially parallel relation and extending over the support in position to engage the work. 22. A folding machine having, in combination, a support for the work, an edge gage, and two rotary shafts arranged in substantially parallel relation and extending over the support in position to engage the work, one of said shafts having its work-engaging portion threaded. to feed the work past the age. g 23. A folding machine-having, in combination, a support for the work,an edge gage, means for heating the gage, and a rotary threaded member overlying both the gage and the work support and ezgtendingclose to the gage. 24. The method of folding a piece of sheet material which'comprises coating the margin on one side with an adhesive substance which contracts upon application to it of heat, applying heat curl toward the coated side,'and pressing the curled margin upon the material.

25. The method of folding a piece of sheet material which comprises coating a margin whereby the margin is caused to thereof with a cementwhich is normally non-tacky, but" may be rendered tacky by heat rendering the cement tackyby applying heat to it, imparting a bend to the margin while it is heatedand thereafter laying the bent margin over upon the body portion of the material and ressing it into place.

' 26. The method of folding a piece of sheet material which comprises coating a margin thereof with a cement which is normally non-tacky but may be rendered tacky by heat rendering the cement tacky byapplying heat progressively to the margin of the material and at the-same time imparting a bend to the margin, and progressive] laying the bent margin over upon the b0 y the material and pressing it into p ace.

' ortion of 279A folding machine having, in combination,

a worksupport, a, gage member adapted to engage the margin of the work as it is fed through the machine to im art a bend to said margin and'thereby initiate a fold, means for heating said member and thereby the margin of the work, and means for pressing the fold.

28. A foldin machine having, in combination, a .wor support, a gage member adapted to engage the margin of the work as-it is fed through the machine to impart a bend to said margin and thereby initiate a fold, means for heating said member and thereby the margin of the work, and an unheated member for pressing the fold.

In testimony whereof I have signed my name to this 'ecification.

oL FORD K. MAcDONALD. 

